The invention relates an aluminium 2-stroke engine cylinder and the crank case assembly, in which a cylinder flange rests in sealing manner over its entire area upon a corresponding counter-surface of the crank case and a deformable packing lies between the sealing surfaces and in which the flange is tightened to the crank case by means of screws.
The tightening of the flange with screws upon the crank case frequently leads to a bending of the flange. As a consequence of this, distortions frequently occur in the working surfaces of the cylinder which are detrimental to the satisfactory running of the piston in the cylinder and can even, in individual cases, lead to piston seizing. The bending of the flange as described can be eliminated by a sufficiently stable construction. However, the reinforcements necessary for this purpose signify an undesired increase of the weight of the cylinder.